My son is 18yo, with the retirement age likely to revise to 67yo, is it wise for him to open the SRS account now to lock the 62yo withdrawal? Thanks?

Yes, definitely. You can open the account online too, I did that with mine (DBS). No need to walk in to any branch. That saves you time.

Yes that is a good idea. You just need to open and put in $1 to lock down the age. A simple process and costs you $1.